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No. 6l2,l69. Patented-Oct. ll, I898. J. W. MUNSON.

PUNCH FDRSTENCIL CUTTING MACHINES.

(Application filed Nov. 4, 1897.)

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UNITED STATES PATENT @EEICE.

JOHN WV. MUNSON, OF NEW YORK, N. Y.

PUNCH FOR STENCIL-CUTTING MACHINES.

SPECIFICATION forming part of Letters Patent No. 612,169, dated October 11, 1898. Application filed November 4, 1897 Serial No. 667,343. (No model.)

To all whom it may concern:

Be it known that I, JOHN W. MUNsoN, a citizen of the United States, residing at New York city, in the county of New York and State of New York, have invented certain new and useful I Improvements in Punches for Stencil-Outtin g Machines, of which the following is a full, clear, and exact specification.

This invention is an improvement relating to punches, and more particularly relates to the manufacture of punches for letters and figures as used in great variety for commercial and manufacturing purposes for perforating paper, thin sheet metal, or any other material in thin sheet form; but is especially designed for producing punches for the letters and figures as used in stencil-cutting maeconomically interchangeable punches at a low cost of manufacture with comparatively cheap labor, thus enabling me to place on the market a stencil-cutting machine which is within reach of every merchant, manufacturer, and producer and which has heretofore been very expensive on account of the expensive punches, which are the principal expense and source of trouble of the present existing machines.

Figures 1 and 2 represent a plan and side view, respectively, of a punch made, in its preferred form, of sheet metal and representing the letter K but any other letter or figure may be equally well produced by the same process. Fig. 3 represents asection of the punch on line 3 3 of Fig. 1. The parallel lines represent the fiber of the sheet metal in the distorted form and show the punch before it has the lower or working surface ground. Fig. 4 represents a section of the punch similar to that of Fig. 3, but having its lower or working surface ground ofi, thereby producing the sharp cutting edge of the punch.

In order to show clearly and fully the nature and scope of my invention and its relation to the art, it is deemed necessary to set forth as briefly as possible the state of this particular branch of that art and the conditions thereof under which arise the desirability and the importance of my invention. In manufacturing sheet-metal punches for this class of machines the general custom has been to punch out the letter separately,which sometimes consists of a single piece, but more frequently is formed of several sections, and then riveting these sections on a base, and thereby produce the punch. It is obvious that it is indispensable, and itis calculated to make these punches perfectly interchangeable, so that new ones may at any time be ordered to replace punches in the machines after they are worn out on account of the frequent recurrence of certain letters of cutting the same out of a solid-steel block or,

casting the same in. molds and then dressing or filing the same to exact shape, all of which are, however, expensive to produce, as the punch must fit its die very closely in order to give a clean and clear out, leaving no ragged edges in the stencil-blank. After having taken all possible pains and care in the manufacture of these dies they are generally hardened, which hardening process is liable to distort them, crack, and even break them, thereby making them totally useless, and thus involving a loss to the manufacturer.

c Having now explained as briefly as possible the nature of the objections which exist in practice in the manufacture of the present forms of dies, I will now describe the features of my improved punch whereby these objections are obviated.

Referring to the drawings of Figs. 1 and 2, the stock or material from which the blank 16 of my improved punch is made is of bright sheet-steel of a homogeneous nature and of a tenacious character. The blank 16 is rigidly attached to the stencil-cutting machine by screws passing through two holes 1'7 and 18, which are preferably made larger than the body of the screw for the convenience of adj usting the punch to the die when assembling the stencil-cutting machines.

To manufacture economically strictly interchangeable punches, I first make a master punch and die of all letters and figures desired to be produced, which are hardened, ground, and lapped, and made in the best manner known to the art of tool-makin g Having thus produced the master punch and die of a desired letter, (shown in the drawings as the letter K,) they are placed in a punch-press in such a manner that when the punch moves downward into its corresponding die the same enters the die a distance of about one-half of the thickness of the sheet metal from which the stencil-punch is made, thereby forcing a portion of the blank, when inserted between them, into the master-die of exact configuration or counterpart of the master-punch and producing on one side of the blank 16 a recess 19 and on the other the projection 20; The projecting surface 20 will, as is the case in all punch presswork, have rounded corners, as at 21, which surface may then be ground, as indicated by the dotted line 22, producing the sharp cutting surface 23, with the sharp corners 24 of Fig. 4, of exact shape of the master-punch.

From the commercial point of view it is of great importance to state that the same master punch and die are used to produce the die for the stencil-cutting machine, as in this case the master-punch is simply forced down into the master-die a little farther than the thick ness of the blank 16, producing a perforation in that blank, which perforation is again the exact counterpart of that master-die. The same master punch and die will therefore produce the punch as well as the die for the stencil-cutting machine, all of Which will be interchangeable and produced on the same machine, requiring no further outlay of tools in the manufacture of the same. Furthermore, I wish to state that the material from which the punches are made must be of a ductile, homogeneous, and tenacious character, and I have illustrated in Figs. 3 and 4 the fibers of the material by the lines a, I), c, d, e, f, and g in their natural state in the blank 16, as well as in the distorted state of the depressed portion of that blank.

It is obvious that great care must be observed not to Weaken the fibers of the blank too much in forcing the depressed portion too far through the blank, so that the same becomes weakened and disabled for the purpose for which it is designed.

In adapting my improved punch for perforating thin sheet-brass as frequently used for stencil-blanks I prefer to fill the recess 19 with a piece of sheet metal, lead, solder,or any other composition of metal, as well known in the art and shown in Fig.4 by the numeral 19".

I claim as my invention- As a new article of manufacture, a punch made of sheet metal, consisting of a baseplate having a portion partly forced through the same, forming a recess on one side and a projection on the other, the recess being filled with a metal to prevent the partly-punchedthrough portion from being forced back; the projection having its lower surface ground so as to form cutting edges, substantially as described.

JNO. V. MUNSON.

\Vitnesses:

GEO. E. SMART, JAMES E. HAMILTON. 

